Log message:
Drop superfluous PKG_DESTDIR_SUPPORT, "user-destdir" is default these days.
Mark packages that don't or might probably not have staged installation.

Log message:
Import py26-pyamg-1.0.0 as wip/py-pyamg.

AMG is a multilevel technique for solving large-scale linear systems with
optimal or near-optimal efficiency. Unlike geometric multigrid, AMG requires
little or no geometric information about the underlying problem and develops a
sequence of coarser grids directly from the input matrix. This feature is
especially important for problems discretized on unstructured meshes
and irregular grids.